Bitstream encoding and file format designed for efficient distribution of sound files over moderate bandwidth connections; may be used at higher data rates for better fidelity. ADIF stands for Audio Data Interchange Format and consists of a brief header that precedes AAC data in a file. Note that the compression approach in AAC_MP2 (used in this format) was subsequently refined as AAC_MP4, which requires a different decoder.

Local use

LC experience or existing holdings

None

LC preference

The Broadcast WAVE format (either version, WAVE_BWF_1 or WAVE_BWF_2), wrapping LPCM, is preferred as the archival master format for mono and stereo audio when reformatting analog sound recordings. Preferences for born-digital acquisitions have not been formally established as of this writing, but acceptable formats will certainly include WAVE, MP3, AAC, and possibly others.

Sustainability factors

Disclosure

Open standard. Developed through ISO technical program JTC 1/SC 29 for coding of audio, picture, multimedia and hypermedia information by Working Group 11 (WG11) aka the Moving Picture Experts Group (MPEG).

According to the Audio Coding Wiki, which is no longer available as of June, 2010, the ADIF format actually is just one header at the beginning of the AAC file. And the rest of the data are consecutive raw data blocks. This file format is meant for simple local storing purposes unlike ADTS or LATM which are meant for streaming AAC. The ADIF header is made up of the following tagged elements; the field size in bits is provided in the parentheses, followed by a comment:

Useful references

"MP3 and AAC Explained" is a 1999 article by Karlheinz Brandenburg, Fraunhofer Institute, Erlangen, Germany. It has good detail but with a focus on AAC_MP2. It is available in several locations and at least two forms.

MP3 and AAC Explained (as PDF) (http://www.iis.fraunhofer.de/content/dam/iis/en/dokumente/AMM/Conference-Paper/AES17_mp3-and-AAC-explained-1.pdf). As published in proceedings of the 17th AES International Conference on High Quality Audio Coding, 1999, Sept 2-5.